textarea文本禁止空格换行

ng-keydown="ctrl.checkEnter(event)"

vm.checkEnter = function(e){
        var et = e || window.event;
        var keycode = et.charCode || et.keyCode;
        if (keycode == 13) {
            if (window.event) {
                window.event.returnValue = false;
            } else {
                e.preventDefault(); //for firefox
            }
        }
    };